Is a 3-Month Notice for Resignation vs. 1-Month for Termination Legal? Let's Discuss!

I would like to hear from all of you on the separation clause. I read in one of the employment contracts under the separation section that if an employee resigns from the services, they need to serve a 3-month notice period, and if the company terminates an employee, it will give a 1-month notice period or salary in lieu. I wanted to check the legality of this clause.

Regards,
Anjali Sarin

Does that mean that if an employee agrees to the contract, then it is lawful? Or if the employee disagrees with the clause, what happens then?